High-efficiency and light-adjustable lighting means of two-electrode lamp

ABSTRACT

A lighting and starting device for two-electrode lamp includes a plurality of voltage-multiplier rectifying circuits parallelly connected to two electrodes of the lamp with stepping voltages, for instance, high, medium and low voltage levels, whereby upon selection of the desired voltage level, the light of the lamp can be adjusted optimumly.

BACKGROUND OF THE INVENTION

A conventional fluorescent lamp has the following disadvantages:

1. When starting the conventional fluorescent lamp, a high current must be applied to heat the lamp filaments to easily blacken the tube to ultimately fail.

2. The electromagnetic waves caused from the high frequency induction coil for starting the fluorescent lamp is hazardous to human health.

3. The lamp is not adjustable for varying the illumination or light intensity, being unsatisfactory for the lamp user.

The present inventor has found the drawbacks of conventional fluorescent lamp and invented the present device for obtaining a two-electrode lamp having high efficiency and being adjustable for lamp.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a lighting device for two-electrode lamp including a plurality of voltage-multiplier rectifying circuits parallelly connected to two electrodes of the fluorescent lamp with stepping voltages, for instance, high, medium and low voltage levels, whereby upon selection of the desired voltage level, the light of the fluorescent lamp can be adjusted optimumly.

Another object of the present invention is to provide a protective device to limit current or to prevent from over current as fed back by the reverse voltage from the lamp and led to the lighting circuit of the two-electrode lamp.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a circuit diagram of the present invention.

FIG. 2 shows a double-voltage rectifying circuit as included in the present invention.

FIG. 3 shows a quadruple-voltage rectifying circuit existing in the present invention.

FIG. 4 shows an octa-voltage rectifying circuit in the present invention.

FIG. 5 is an illustration when added with a further light-adjusting device of the present invention.

FIG. 6 shows a fluorescent lamp as protected in accordance with the present invention.

DETAILED DESCRIPTION

As shown in the drawing figures, a preferred embodiment of the present invention comprises a plurality of (or three) voltage-multiplier rectifying circuits Ckt₁, Ckt₂ and Ckt₃ parallelly connected across two electrodes of a fluorescent lamp FL.

As shown in FIG. 2. The first voltage-multiplier rectifying circuit Ckt₁ of full-wave bridge type rectifier is described hereinafter.

An alternative current (AC) power source supply having voltage V₀ is applied to the circuit Ckt₁ through points A and C. The operation principles are shown as follows:

First Cycle

When point A meets a positive half cycle of voltage V₀ and point C meets a negative half cycle, the diode D₃ is conducted (D₅ is interrupted) and the capacitor C₁ is charged up to the voltage V₀. Meanwhile, when point A meets the positive half cycle of voltage V₀ and point C meets negative half cycle of voltage V₀, the diode D₆ is conducted (D₄ is interrupted) and the capacitor C₄ is charged up to voltage V₀.

During the positive and negative alternation, the positive electricity as charged to the capacitor C₁ will be discharged through diode D₁ and resistor R₁ and output through a first contactor a₁ of a first electrode (or positive electrode) of the fluorescent lamp FL (FIG. 1), and the negative electricity will be output through diode D6, diode D8, resistor R4 and a second contactor b2 of a second electrode (or negative electrode) of the fluorescent lamp FL. Meanwhile, the positive electricity charged to the capacitor C₄ will be discharged through diode D₃, diode D₁ and resistor R₁ and output through the first contactor a₁ of the first electrode of the lamp FL; and the negative electricity thereof is output through diode D₈, resistor R₄ and the second contactor b₂ of the second electrode of the lamp FL.

Second Cycle

When point A meets a negative half cycle of the voltage V₀, and point C meets a positive half cycle of voltage V₀, the diode D₄ is conducted (D₆ is interrupted) and the capacitor C₂ is charged up to the voltage V₀. Meanwhile, when point A meets the negative half cycle and point C meets positive half cycle, the diode D₅ is conducted (D₃ interrupted) and the capacitor C₃ is charged up to the voltage V₀.

During the alternation, the positive electricity as charged to the capacitor C₂ will be discharged through diode D₂ and resistor R₂ and output through the second contactor a₂ of the first electrode of the lamp FL, and the negative electricity is output through diode D₅, diode D₇ and resistor R₃ and output through the first contactor b₁ of the second electrode (or negative electrode) of the lamp FL. Meanwhile, the positive electricity charged to the capacitor C₃ will be discharged through diode D₄, diode D₂ and resistor R₂ and output through the second contactor a₂ of the first electrode of the lamp FL, and the negative electricity will be output through the diode D₇ and resistor R₃ and output through the first contactor b₁ of the second electrode of the lamp FL.

Accordingly, the contactors a₁, a₂ of the first electrode of the lamp FL are connected in parallel and the contactors b₁, b₂ of the second electrode are also connected in parallel to output a voltage of 2V₀ since capacitors C₁, C₃ are connected in series, and capacitors C₂, C₄ are also connected in series.

For calculating a total impedance value R_(x) of a “loop” of the lighting means as connected with the lamp (having a half-wave internal resistance of R_(x1), R_(x2)), the following formula may, for instance, be used:

{overscore (R)} ₁ =R ₁ +R ₃+{1÷[2πf(C ₁ +C ₃)]}=R _(x1)

{overscore (R)} ₂ =R ₂ +R ₄+{1÷[2πf(C ₂ +C ₄)]}=R _(x2)

R _(x)=1÷[(1÷R _(x1))+(1÷R _(x2))]

The alternation of the positive or negative pulses of an alternative current (AC) power source supply to forwardly conduct diodes and reversely interrupt the diodes and to discharge the capacitors as already being charged to thereby multiply the voltage. For instance, the voltage V₀ of power source will be multiplied to be 2V₀ to eliminate the high frequency induction coil or transformer of a starter as required by a conventional fluorescent lamp. The electromagnetic waves as caused by the high frequency induction coil or transformer of conventional fluorescent lamp will then be prevented in accordance with the present invention, thereby being helpful for human health.

The first rectifying circuit Ckt₁ can produce double voltage, i.e., 2V₀; and the second rectifying circuit Ckt₂ (FIG. 3) can produce quadruple voltage, 4V₀; and the octa-voltage, 8V₀ will be obtained by the third rectifying circuit Ckt₃ (FIG. 4) as hereinafter described.

By selectively connecting either of the rectifying circuits Ckt₁ or Ckt₂ or Ckt₃, three (or plural) multiplied voltage levels can be chosen and applied to the first and second electrodes of the fluorescent lamp FL for adjusting the light intensity of the fluorescent lamp. Namely, Ckt₁ (2V) may obtain a high light illumination, Ckt₂ (4V) obtaining a medium light, and Ckt₃ (8V) obtaining a low light illumination.

As shown in FIG. 3, a second voltage-multiplier rectifying circuit (full-wave bridge type) Ckt₂, as parallelly connected to the lamp FL as shown in FIG. 1, is described as hereinafter. V₀ is the alternative-current (AC) power source supply, alternatively delivering a positive half cycle and a negative half cycle to the circuit Ckt₂ through the point A and point C continuously. The operation principles are described as follows:

First Cycle

When point A is positive and point C is negative, the diode D₁₇ is conducted and the capacitor C₁₇ is charged to the voltage V₀. When point A is negative and point C is positive, the diode D₁₇ is interrupted and the diode D₁₉ is conducted to charge the capacitor C₁₇ to the voltage V₀ which is added on the voltage V₀ of power source supply to further charge the C₁₃ to be 2V₀ (V₀+V₀=2V₀).

During the alternation of positive and negative electricity, the positive electricity of C₁₃ is discharged through the first contactor a₁ of the first electrode of the lamp FL through D₁₅, D₁₃, D₁₁ and R₁₁ and the negative electricity of C₁₃ is discharged through the second contactor b₁ of the second electrode of the lamp FL through D₂₁, R₁₃.

Meanwhile, when point A is positive and point C is negative, D₁₆ is conducted and C₁₆ is charged to the voltage V₀. When point A is negative and point C is positive, D₁₆ is interrupted and D₁₄ is conducted to charge C₁₆ to the voltage V₀ which is added on with the voltage V₀ of power source supply to further charge C₁₂ to be 2V₀. During the alternation of positive and negative electricity, the positive electricity of C₁₂ is discharged through a₂ of the lamp FL through D₁₂, R₁₂ and the negative electricity is discharged through b₂ of lamp FL through D₁₈, D₂₀, D₂₂ and R₁₄.

Second Cycle

When point A is negative and point C is positive, D₁₅ is conducted and C₁₅ is charged to V₀. When point A is positive and point C is negative, D₁₅ is interrupted and D₁₃ is conducted to charge C₁₁ to be 2V which is obtained by the voltage V₀ of C₁₅ plus the voltage V₀ of power source. During the alternation of the positive and negative electricity, the positive electricity of C₁₁ is discharged through a₁ of lamp FL through D₁₁, R₁₁, and the negative electricity discharged through b₁ of lamp FL through D₁₇, D₁₉, D₂₁ and R₁₃.

Meanwhile, when point A is negative and point C is positive, D₁₈ is conducted and C₁₈ is charged to voltage V₀. When point A is positive and point C is negative, D₁₈ is interrupted and D₂₀ is conducted to charge C₁₈ to V₀ which is added with V₀ of power source to further charge C₁₄ to be 2V₀. During the alternation of positive and negative electricity, the positive electricity of C₁₄ is discharged through a₂ of lamp FL through D₁₆, D₁₄, D₁₂ and R₁₂, and the negative electricity discharged through b₂ of FL through D₁₂, R₁₄.

By the way, C₁₁ is connected in series with C₁₃ to obtain 4V₀ (2V₀+2V₀=4V₀); while C₁₂ is connected with C₁₄ in series to obtain 4V₀ to obtain a quadruple voltage (4V₀) of the power source when the a₁, a₂ are parallelly connected and the b₁, b₂ are also parallelly connected to the lamp FL.

As shown in FIG. 4 of octa-voltage multiplier of full-wave bridge type rectifier connected to points A and C of the AC power source, the first contactor a₁ of the first electrode of the lamp FL is connected with the elements including D₂₉, D₂₇, D₂₅, D₂₃, D₂₁, R₂₁, C₃₁, C₂₉, C₂₃ and C₂₁; the second contactor a₂ connected with D₃₀, D₂₈, D₂₆, D₂₄, D₂₂, R₂₂, C₃₂, C₃₀, C₂₄ and C₂₂; the b₁ of the second electrode connected with D₃₁, D₃₃, D₃₅, D₃₇, D₃₉, R₂₃, C₂₅, C₂₇, C₃₃ and C₃₅; and the b₂ connected with D₃₂, D₃₄, D₃₆, D₃₈, D₄₀, R₂₄, C₂₆, C₂₈, C₃₄ and C₃₆. When C₂₁, C₂₃, C₂₅, C₂₇ are connected in series, 8V₀ is obtained at a₁, b₁; and C₂₂, C₂₄, C₂₆, C₂₈ connected in series, 8V₀ is obtained at a₂, b₂. Therefore an octa-voltage (8V₀) can be obtained.

So, multiplier voltage of 2V₀, 4V₀ and 8V₀ can be selected from FIGS. 2, 3, 4 in accordance with the present invention to respectively obtain illumination light intensity of the florescent lamp FL explained as follows:

First Step for Starting or Lighting Lamp

By using the third full-wave voltage-multiplier bridge rectifying circuit Ckt₃ of FIG. 4 to parallelly connect a₁, a₂ to the first electrode of fluorescent lamp FL to supply positive charge to the first electrode of 8V₀ high voltage and also to parallelly connect b₁, b₂ to the second electrode of FL to supply negative charge to the second electrode of 8V₀ voltage, the lamp FL is lighted by reducing the resistance in the lamp tube by the high voltage. However, the current is low so that the first step for lighting the lamp is a low light intensity (or low brightness) illumination.

Second Step for Lighting Lamp

By using the second rectifying circuit Ckt₂ as shown in FIG. 3 to connect a₁, a₂, b₁ and b₂ respectively to the two electrodes of the lamp FL to apply the medium voltage (4V₀) to the lamp, a second step for lighting the lamp at a medium light intensity illumination with medium current which is still higher than the current of first step (by Ckt₃) to further reduce the internal resistance in the lamp and thus brighter than that of Ckt₃.

Third Step

By using the first rectifying circuit Ckt₁ as shown in FIG. 2 to apply the low voltage (2V₀) to the lamp FL, a third step for lighting the lamp FL at the brightest level than the second step since maximum current and lowest voltage is applied to the lamp to minimize the internal resistance in the lamp tube.

Therefore the light intensity of the lamp can be adjusted stepwise by selecting the desired rectifying circuit. Naturally, the circuits are not limited to Ckt₁, Ckt₂ and Ckt₃ as aforementioned in accordance with the present invention.

The lower the internal resistance in the lamp tube is, the higher the current in the tube will be, thereby emitting more electrons for strongly ionizing vapor in the tube for glowing the lamp brighter.

As shown in FIG. 1 for showing a starter device, since the first or positive electrode (filament) Fa is far apart from the second or negative electrode (filament) Fb of the lamp FL, an outer negative electrode S_(b) (which may be an electrically conductive ring or metal ring) is closely disposed about the positive electrode Fa as partitioned by an electrically insulative tube wall of the lamp FL and is connected to the negative electrode Fb by a limiting-current resistor Rb; and an outer positive electrode Sa (which may be an electrically conductive ring or metal ring) is closely disposed about the negative electrode Fb as partitioned by the electrically insulative tube wall of the lamp and is connected to the positive electrode Fa by another limiting-current resistor Ra.

Since each outer electrode Sb or Sa is quite close to the electrode Fa or Fb in the lamp tube by the insulative tube wall to play as a capacitor, the voltage between the outer electrode with the electrode (filament) in the lamp tube will be discharged to have the function of a starter for starting the fluorescent lamp FL.

Accordingly, a conventional starter for boosting the voltage in order to start the fluorescent lamp will be eliminated in accordance with this starter device of the lamp FL as above-mentioned.

As shown in FIG. 6, each contactor a₁, a₂, b₁, b₂ is connected to each electrode Fa or F_(b) by a limiting-current resistor R to limit the current under a safety value in consideration of a “critical impact effect” for protecting the filaments Fa, Fb and the lamp FL, for instance, for preventing from damage and blackening of the tube.

The present invention provides a fluorescent lamp which is light adjustable, safely protected and not hazardous as caused by the electromagnetic wave, thereby serving for convenient, safe and energy-saving use.

As shown in FIG. 5, each terminal such as point C (or point A) is selectively connected with a plurality of selecting switches S, for instance, Nc for power off; a first switch (numeral “1”) for a first current supply and first light intensity; a second switch (numeral “2”) connected with a resistor R_(s) to the circuit for a second (lower) current supply and second (weak) light intensity. A third switch (“3”) may also be added. However, such a switch device is so conventional and can be modified by those of skill in the art.

The present invention may be modified without departing from the spirit and scope of this invention. The voltage multipliers are also not limited to voltage doublers.

The two-electrode lamp of the present invention may refer to a fluorescent lamp, and other two-electrode illuminators. 

We claim:
 1. A lighting means of two-electrode lamp comprising: a plurality of voltage-multiplier bridge rectifying circuits selectively and parallelly connected to a positive electrode and a negative electrode of a two-electrode lamp, having stepwise rating of voltage and current values of said rectifying circuits for operatively adjusting a light intensity or brightness of the two-electrode lamp; each said voltage-multiplier rectifying circuit connected to an alternative-current (AC) power source supply and operatively alternatively forward conducting a plurality of diodes or reversely interrupting a plurality of said diodes, and having a plurality of capacitors connected between said positive and negative electrodes of said lamp and respectively connected to said diodes and alternatively charging or discharging for outputting positive or negative electricity of a multiplied voltage to said positive and negative electrodes for lighting said two-electrode lamp; and a starter device including: an outer negative electrode formed as a first electrically conductive ring and closely disposed about the positive electrode as partitioned by an electrically insulative tube wall of the lamp and connected to the negative electrode by a first limiting-current resistor; and an outer positive electrode formed as a second electrically conductive ring and closely disposed about the negative electrode as partitioned by the electrically insulative tube wall of the lamp and connected to the positive electrode by a second limiting-current resistor; each said outer electrode positioned closely to each said electrode in the lamp tube as partitioned by the tube wall for forming a capacitor operatively charging and discharging for starting the lamp. 